vists a node's left child first, then the node itself, then its right child. This is the one to use if you want the output sorted according to the compare function.
is not implemented for [balanced binary trees][glib-Balanced-Binary-Trees]. For [n-ary trees][glib-N-ary-Trees], it vists the root node first, then its children, then its grandchildren, and so on. Note that this is less efficient than the other orders.
visits the node's children, then the node itself.
visits a node, then its children.
Specifies the type of traversal performed by g_tree_traverse(), g_node_traverse() and g_node_find(). The different orders are illustrated here: